1. Field of the Invention
The present invention relates to an information reproducing apparatus for reproducing digital information recorded on a recording disk such as a DVD, and more particularly to an information reproducing apparatus capable of prohibiting reproduction of digital information that has been illegally or unfairly copied.
2. Description of the Related Art
A DVD is a recording medium having a large recording capacity, and can record, for example, digital video information equivalent to one volume of moving picture film. Because of this large capacity, a DVD has come to be distributed as an image recording medium for replacing a video cassette of VHS system. A DVD exists in two types; a DVD onto which a recording or a rewriting cannot be done (It is referred to as a xe2x80x9cread-only DVDxe2x80x9d, hereinafter.), and a DVD onto which a recording or a rewriting can be done (It is referred to as a xe2x80x9crecordable DVDxe2x80x9d, hereinafter.). When a recordable DVD is used, it is possible to digitally copy the whole content of a moving picture recorded on the DVD.
Along with the distribution of the recordable DVD, there has been developed a system for digitally transmitting a moving picture or the like from a broadcasting station to general subscribers. When this system has been achieved, it becomes possible for subscribers to not only enjoy watching a high-definition moving picture at home but also digitally record the moving picture transmitted from the broadcasting station onto a DVD and prepare a replica disk in an easy manner.
On the other hand, the act of copying a moving picture or the like without permission is restricted by the copyright law, etc. Particularly, when a moving picture or the like is copied digitally, there occurs no quality degradation in the moving picture copied. Accordingly, it is necessary to severely restrict the copying of digital video information using a DVD in order to promote the distribution of DVD as well.
In order to restrict the recording or copying of digital video information, various methods have been proposed. For example, there is proposed a method of embedding identification information for restricting the copying into digital video information at the time of recording the digital video information onto a DVD. Such a system is generally called a CGMS (Copy Generation Management System). This identification information represents one of the following: (1) prohibiting the copying (hereinafter to be referred to as xe2x80x9cNever Copyxe2x80x9d), (2) permitting the copying only once (hereinafter to be referred to as xe2x80x9cOne Copyxe2x80x9d), and (3) permitting the copying without restriction (hereinafter to be referred to as xe2x80x9cCopy Freexe2x80x9d). When digital video information embedded with this kind of identification information is copied onto other DVD, a recording apparatus reads out the identification information from within the digital video information, and if this identification information shows Never Copy, the recording apparatus does not record this digital video information.
Further, there is also proposed a method of restricting the copying of a picture or a video image by embedding identification information having a function similar to the above into the display range of the image or the video image as a watermark.
Meanwhile, since the DVD is an optical recording medium, a light beam is used in recording and reading the digital video information. Because of this, when recording the digital video information onto the DVD, the digital video information is converted into an RF (Radio Frequency) signal and then recorded onto the DVD. That is, the digital video information is actually recorded onto the DVD as the RF signal.
When reproducing the digital video information from the DVD, the RF signal is read from the DVD and then converted into the digital video information with a decoder.
It is possible to detect the CGMS and the watermark from the digital video information. However, it is not possible to directly detect them from the RF signal. This means that the restriction of the illegally or unfairly copying of the digital video information using the CGMS and the watermark is effective only after the RF signal is converted into the digital video information.
Therefore, the restriction of the copying of the digital video information using the CGMS and the watermark is not effective in an act of copying the RF signal from one DVD to another. If an act of reading the RF signal from the DVD and directly recording it onto another DVD is done, the CGMS and the watermark is not useful.
It is therefore an object of the present invention to provide an information reproducing apparatus capable of prohibiting reproduction of digital information which has been copied by copying an RF signal from one recording disk to another.
An information reproducing apparatus in accordance with the present invention is an apparatus for reading record information from a recording disk and outputting the read record information in order to reproduce the record information recorded on the recording disk.
The record information includes: image information which represents an image or a picture; identification information which represents any one of at least never copy and copy free.
The never copy indicates that copying of the record information is prohibited. The copy free indicates that the copying of the record information is permitted.
The information reproducing apparatus comprises: a read device for reading the record information from the recording disk; a first determination device for determining whether the identification information included in the read record information indicates the never copy or the copy free; a second determination device for determining whether the recording disk is a recording disk of a recordable type or a recording disk of a read-only type; an output control device for determining on the basis of determinations of the first determination device and the second determination device whether outputting the read record information is permitted or prohibited; and an output device for outputting the read record information in accordance with a determination of the output control device.
As stated above, the identification information indicates any one of the never copy and the copy free. For example, two different values may be used as the identification information. One is used as a value indicating the never copy. The other is used as a value indicating the copy free. Alternatively, only one value may be used as the identification information. In this case, when the value is included in the record information, it may be determined that the record information is the never copy. When the value is not included in the record information, it may be determined that the record information is the copy free.
In the above-stated information reproducing apparatus, the read device reads the record information from the recording disk. The first determination device determines whether the identification information included in the record information indicates the never copy or the copy free. Therefore, a copy restriction status of the record information can be determined.
The second determination device determines whether the type of recording disk is a recordable type or a read-only type. Therefore, the type of the recording disk can be determined. In addition, the recording disk of the recordable type is a recording disk that information can be recorded thereon once or many times. Both a rewritable disk and a recordable disk are included in the recording disk of the recordable type.
The output control device determines on the basis of the identification information and the type of recording disk whether outputting the read record information is permitted or prohibited. The output device outputs the record information in accordance with a determination of the output control device.
For example, when the identification information indicates the copy free and the type of recording disk is the recordable type, it is recognized that the record information that is allowed the copying has been recorded on the recordable type disk. This is normal. At this time, the output control device determines that outputting the record information is permitted. The output device therefore outputs the record information.
On the other hand, when the identification information indicates the never copy and the type of recording disk is the recordable type, it is recognized that the record information that is prohibited the copying has been recorded on the recordable type recording disk. This is abnormal. It can be expected illegal or unfair copying. If an RF signal is directly copied from one disk to another, this case occurs. In such a case, the output control device determines that outputting the record information is prohibited. The output device therefore does not output the record information. Thus, reproduction of an illegally or unfairly copied record information can be prevented.
In the above-stated information reproducing apparatus, the second determination device may includes: a detection device for detecting a form of a track formed on a surface of the recording disk; and a disk determination device for determining on the basis of a detection of the detection device whether the recording disk is the recording disk of the recordable type or the recording disk of the read-only type.
The recordable type recording disk and the read-only type recording disk are different from each other in physical structure. The second determination device determines the type of recording disk by detecting a difference in physical structure of the recording disk.
In the above-stated information reproducing apparatus, the second determination device may includes: a detection device for detecting a wobble of a track formed on a surface of the recording disk; and a disk determination device for determining on the basis of a detection of the detecting device whether the recording disk is the recording disk of the recordable type or the recording disk of the read-only type.
In the recordable type recording disk, the track has the wobble. In the read-only type recording disk, the track does not have the wobble. The second determination device determines the type of recording disk by detecting presence or absence of the wobble.
In the above-stated information reproducing apparatus, the second determination device may includes: a detection device for detecting a loop track formed on the surface of the recording disk; and a disk determination device for determining on the basis of a detection of the detecting device whether the recording disk is the disk of the recordable type or the disk of the read-only type.
Each of the recording disk of the recordable type and the recording disk of the read-only type has a spiral track. The spiral track is formed on a surface of the recording disk. The record information is recorded on the spiral track. Only the recording disk of the recordable type further has a loop track. The loop track is formed on the surface of the recording disk together with the spiral track. The loop track is different from the spiral track in form. The second determination device determines the type of recording disk by detecting presence or absence of the loop track.
In the above-stated information reproducing apparatus, the second determination device may includes: a detection device for detecting the disk information from the recording disk; and a disk determination device for determining on the basis of a detection of the detecting device whether the recording disk is the recording disk of the recordable type or the recording disk of the read-only type.
The recording disk has disk information. The disk information is recorded on the recording disk as digital data. The disk information indicates the type of the recording disk. The second determination device determines the type of recording disk by detecting the disk information.
In the above-stated information reproducing apparatus, the second determination device may includes: a detection device for detecting the standard information from the recording disk; and a disk determination device for determining on the basis of a detection of the detecting device whether the recording disk is the recording disk of the recordable type or the recording disk of the read-only type.
The recording disk has standard information. The standard information is recorded on the recording disk as digital data. The standard information indicates a standard of the recording disk. The standard of the recording disk is different depending on the type of recording disk. The second determination device determines the type of recording disk by detecting the standard information.